POWER LOSS (W) LTC7880 60V Dual Output Step-Up Controller with Digital Power System Management FEATURES DESCRIPTION 2 n PMBus/I C Compliant Serial Interface The LTC 7880 is a dual PolyPhase DC/DC synchronous 2 Telemetry Read-Back Includes Input and Output step-up switching regulator controller with I C-based PM- Voltage and Current, Temperature and Faults Bus compliant serial interface. This controller employs a Programmable Voltage, Current Limit, Digital constant-frequency, current-mode architecture, with high Soft-Start/Stop, Sequencing, Margining, OV/UV/OC, voltage input and output capability along with program- Frequency, and Control Loop Compensation mable loop compensation. The LTC7880 is supported by n Output Error Less Than 0.5% Over Temperature the LTpowerPlay software development tool with graphical n Integrated 16-Bit ADC and 12-Bit DAC user interface (GUI). n Internal EEPROM with ECC and Fault Logging Switching frequency, output voltage, and device address n Integrated N-Channel MOSFET Gate Drivers can be programmed both by digital interface as well Power Conversion as external configuration resistors. Parameters can be n Wide Input Voltage Range: 5V to 40V set via the digital interface or stored in EEPROM. The n Operates Down to 2.5V After Start-Up gate drive for the LTC7880 can be programmed from n V , V Range: Up to 60V OUT0 OUT1 6.3V to 9V to maximize efficiency. Both outputs have an n Analog Current Mode Control independent power good indicator and FAULT function. n Accurate PolyPhase Current Sharing for The LTC7880 can be configured for discontinuous (pulse- Up to 6 Phases (50kHz to 500kHz) skipping) mode or continuous inductor current mode. n Available in a 52-Lead (7mm 8mm) QFN Package All registered trademarks and trademarks are the property of their respective owners. Protected by U.S. patents, including 5481178, 5705919, 5929620, 6100678, 6144194, 6177787, APPLICATIONS 5408150, 6580258, 6304066, 7420359, 8786268 Patent Pending. Licensed under U.S. Patent 7000125 and other related patents worldwide. n Automotive Always-On and Start-Stop Systems n Industrial and Point of Load Applications TYPICAL APPLICATION 6.8H 3m V IN Efficiency and Power Loss 47F 5V TO 40V + I I VBIAS OUT OUT + DOWN TO 2.5V AFTER I SENSE1 vs Load Current STARTUP IF VBIAS IS I SENSE1 POWERED FROM V OUT 99 20 BG1 SDA BOOST1 SCL 0.1F 5m PMBus V OUT ALERT INTERFACE 24V AT 10A RUN0 SW1 LTC7880 98 15 RUN1 220F TG1 FAULT0 FAULT1 FAULT MANAGEMENT DRV CC PGOOD0 V 97 10 OUT 6.8H 4.7F 3m PGOOD1 FOLLOWS V IN TO/FROM SHARE CLK FOR V > 24V IN OTHER ADI DEVICES + I SENSE0 TSNS1 I 96 5 SENSE0 10nF V = 12V TSNS0 IN BG0 V = 24V 10nF OUT f = 150kHz SW EXTV CC BOOST0 95 0 0.1F 0 5 10 15 20 25 SW0 LOAD CURRENT (A) ITH1 7880 TA01b TG0 ITHR1 + V ITH0 SENSE0 7880 TA01a ITHR0 V V 10nF DD33 GND DD25 100pF 1F 1F *SOME DETAILS OMITTED FOR CLARITY Rev 0 1 Document Feedback For more information www.analog.com EFFICIENCY (%)LTC7880 TABLE OF CONTENTS Features ..................................................... 1 Device Addressing ..................................................26 Applications ................................................ 1 Responses to V Faults .......................................27 OUT Typical Application ........................................ 1 Output Overvoltage Fault Response ...................27 Description.................................................. 1 Output Undervoltage Response .........................27 Table of Contents .......................................... 2 Peak Input Overcurrent Response ......................28 Absolute Maximum Ratings .............................. 4 Responses to Timing Faults ....................................28 Order Information .......................................... 4 Responses to V OV Faults ....................................28 IN Pin Configuration .......................................... 4 Responses to OT/UT Faults .....................................28 Electrical Characteristics ................................. 5 Internal Overtemperature Fault/Warn Response 28 Typical Performance Characteristics .................. 10 External Overtemperature and Undertemperature Pin Functions .............................................. 13 Fault Response ..................................................28 Block Diagram ............................................. 15 Responses to External Faults .................................29 Operation................................................... 16 Fault Logging ..........................................................29 Overview ................................................................. 16 Bus Timeout Protection ..........................................29 2 Main Control Loop .................................................. 16 Similarity Between PMBus, SMBus and I C EEPROM ................................................................. 17 2-Wire Interface ......................................................30 CRC Protection .................................................. 17 PMBus Serial Digital Interface ................................30 Power-Up and Initialization ..................................... 18 PMBus Command Summary ............................ 35 Soft-Start ................................................................ 18 PMBus Commands .................................................35 Event-Based Sequencing ........................................ 19 Applications Information ................................ 40 Shutdown ............................................................... 19 Current Limit Programming ....................................40 + Light-Load Current Operation .................................20 I and I Pins .........................................40 SENSE SENSE OPERATION WHEN V > V Low Value Resistor Current Sensing ....................... 41 IN OUT ........................................20 BOOST Refresh and Internal Charge Pump ........20 Inductor DCR Current Sensing ................................42 Operation at Low SENSE Pin Common Mode Slope Compensation and Inductor Peak Current ....43 Voltage ...............................................................20 Inductor Value Calculation ......................................43 PWM Loop Compensation ......................................20 Inductor Core Selection ..........................................44 Switching Frequency and Phase .............................21 Power MOSFET and Optional Schottky Diode Output Voltage Sensing ..........................................21 Selection .................................................................44 Output Current Sensing ..........................................21 C and C Selection ...........................................45 IN OUT Input Current Sensing .............................................21 Variable Delay Time, Soft-Start and Output Voltage PolyPhase Load Sharing .........................................21 Ramping .................................................................45 External/Internal Temperature Sense ......................22 Digital Servo Mode .................................................46 RCONFIG (Resistor Configuration) Pins ..................22 Soft Off (Sequenced Off) ........................................ 47 Fault Handling .........................................................23 DRV Regulator .................................................... 47 CC Status Registers and ALERT Masking ................. 24 Topside MOSFET Driver Supply (C , D ) ................48 B B Mapping Faults to FAULT Pins ............................26 Undervoltage Lockout .............................................49 Power Good Pins ................................................26 Fault Indications .....................................................49 Serial Interface .......................................................26 Open-Drain Pins .....................................................49 Communication Protection ................................26 Phase-Locked Loop and Frequency Synchronization ......................................................50 Rev 0 2 For more information www.analog.com